My nephew shoplifted in Kmart, hes 20. He was let go with a warning but said he would get a civil fine in the mail. Does he have to appear in court?

Far more information is needed. I need to speak with both your nephew and, with his permission, you about what exactly happened, where and how. I need to see any and all paperwork your nephew was given or that he received in the mail. Telephone me at either (732)932-7226 (office) or (732)710-0004 (cell).

No - usually the "civil penalty" is about $150 - $200".  He will receive a letter in the mail which will have the date of the event and tell him to pay the money immediately.  I suggest someone pay it on his behalf so that Kmart doen not pursue crimunal charges.  By having someone else pay he can protect himself (no admission of guilt) should Kmart decide to sign criminal a chrage.

That depends on exactly what he gets in the mail, which should explain in some detail what his options are.  If it's any kind of legal process at all, he'll have an option, at least, to go to court;  it may be that this will be something that he can simply pay by mail or the internet and be done with.

I don't know of any "civil fine" in New Jersey law, by that name.  There are a number of "civil penalties" that can be imposed for various things, but none that I can think of that would have anything to do with this.  If your nephew isn't clear on what he has to do, after reading whatever comes in the mail, he needs to take the notice to a lawyer.